Furnace wall construction



Feb. 9, 1937. sc

FURNACE WALL CONSTRUCTION Filed April 24, 1931 2 SheetsSheet l INVENTORli: lllllll Feb. 9, 1937. R sc FURNACE WALL CONSTRUCTION Filed April 24,1931 2 Sheets-Sheet 2 INVENTOR Haw/$44 65ml Z ATNORfiEf Patented. Feb.9, 1937 FURNACE WALL CONSTRUCTION Martin Frisch, New York, N. Y.,assignor to Foster Wheeler Corporation, New York, N. YL,

a corporation of New York Application April 24, 1931, Serial No. 532,423

16 Claims.

My invention relates to furnaces, particularly to water walls thereof,and especially to an improved refractory or armor construction for waterWalls.

The general purpose of providing an armor for water walls is to preventthe fire from coming into direct contact with the tubes and also to forma continuous flat or substantially continuous flat non-slagging wallmade up of a plurality of blocks having high heat conductivity. Theseblocks being placed in contact with the tubes assure that substantiallyall of the heat absorbed by the wall is transferred to the water tubesand is thus usefully employed in heating or vaporizing the fluid withinthe tubes.

It has been proposed to provide armor block units, each made up of twomembers having cylindrical tube receiving recesses and curved surfaceseccentric to these recesses. The blocks making up a unit are placed withthe tube receiving recesses on adjacent water tubes and with theeccentric surfaces of the tube blocks in contact with each other.Tension means is employed to rotate or swing the blocks around the tubesand to thus wedge the blocks between and against the tubes due to theeccentric surfaces. While the close contact between the blocks and thetubes resulting from this wedging action assures a good heat transfertherebetween, I have found that proper adjustment of the blocks withrespect to the tube aggregate is difficult due to the tend- 1 ency ofthe wedging action to separate or spread the tubes. In the present.invention I provide means for aligning the tubes and preventingshifting of the tubes due to the wedging action while retaining all ofthe advantages derived from the use of this type of an armor block unit.

These and further objects and advantages will be apparent from thefollowing description considered in connection with the accompanyingdrawings, which are to be taken as a part of this specification and onwhich:

Fig. l is a cross-sectional view of a portion of a boiler furnaceprovided with a water wall;

Fig. 2 is a cross-sectional view showing details of a water wallconstruction in accordance with the invention and taken partly on theline 22 of Fig. 3;

Fig. 3 is an elevational view of several block units making up the waterwall;

Fig. 4 is a cross-sectional view taken on, the line 4-4 of Fig. 3; and

Fig. 5 is a perspective view of a block unit shown in position on a pairof adjacent tubes.

Referring to the drawings, Fig. 1 shows a well known type of water tubeboiler having a furnace chamber I enclosed by vertical walls, includinga rear water wall II and a side water wall 9. A series of verticallyextending water tubes l2 pass through walls 9 and II. The lower ends oftubes l2 of wall H communicate with a header l3 while the upper endscommunicate with a header l4, both of these headers being locatedoutside of the furnace. Similar headers are provided for the tubes inwall 9. It is the usual practice to pass water through tubes l2 eitherbefore it is introduced into the boiler proper or bythermo-syphoncirculation conduits connected to the boiler proper. Anytype of boiler may be used, that illustrated having water tubes I and asteam and water drum Hi. My improved water wall construction may,however, be used elsewhere than in boiler furnaces.

The lower part of furnace I0 is provided with some kind of fuel burningmeans, here shown as a mechanical stoker II. There is thus present inthe lower part of furnace l 0 a fire which radiates heat to thesurrounding walls, including walls 9 and l Water tubes I2 are providedin this wall to absorb this radiant heat. In order that the water tubesshall'not be subjected directly to the intense heat of the fire they areprovided with block units l8 made of east-iron or other suitablerefractory material. I]

The details of the block units in accordance with my invention are shownin Figs. 2 through 5. Each block unit l8 comprises a pair of blockmembers l9 and 20. Members l9 and 20 are identical in form. Each membercomprises a front fire face 2| of substantially rectangular shape and anadjacent convex bearing or contacting surface 22. The bearing surface ofblock I9 is in contact with the bearing surface of block 20 when theblocks are in position on the tubes. Each block is also provided with acylindrical tube receiving recess 23 of substantially the same diameteras the water tubes I2. Each recess 23 is ofsufficient extent to extendaround more than one quarter of -the perimeter of a tube and hence whenblock members of adjacent block units are in place on a tube more thanone half of the surface of the tube is in contact with the blocks. Thebearing surfaces 22 are curved and may be cylindrical and are eccentricwith respect to thetube receiving recesses 23. In the form shown, thesurfaces 22 are drawn. about centers forward of the tube centers and atthe forward edges of contact of the blocks with the tubes.

The side of each block l9 opposite from the tube receiving recess is cutaway at the rear portion thereof as is indicated at 24. A pair of lipsor abutments 25 extend from the block proper on either side of andadjacent to the central part of each block. The central part of eachblock between abutments 25 is formed with a semi-cylindrical recess 26to receive the head of an eye-bolt 21, the shank of which extendsbetween the abutments 25. A portion of the block adjacent to the tubereceiving recess is cut away between the abutments 25, as is shown at 28in order to make room for a rigid backing member, as will be explained.

Rigid backing member 29 comprises a rectangular metallic piece providedwith a flange 30 extending around the four sides thereof. The flanges atthe end of member 29 are provided with apertures through which bolts 3|may be placed when the members 29 are in assembled position. The face ofeach member 29 opposite the side on which the flanges 30 are formed isprovided with a cylindrical tube receiving recess 32. This recess isformed in part by projecting lips 33 which, when assembled, extend intothe recesses 28 in the block members. The diameter of the cylindricalrecess 32 is substantially the same as that of the water tubes. Thelength of members 29 is such that they will extend between two adjacentwater tubes when these tubes are in their normal position.

In assembling my preferred form of water wall the block units comprisingblock members I 9 and 29 are placed in position on pairs of adjacenttubes by placing their respective tube receiving surfaces on the tubesand rotating each block around the tubes until their bearing surfaces 22come in contact with each other. Eye-bolt 21 is then placed in positionbetween abutments 25 on the pair of block members and a pin 34 is passedthrough the substantially cylindrical recess formed betweencorresponding abutments on the two blocks, through the eye of theeye-bolt and through the cylindrical recesses formed between the othertwo corresponding abutments. Pin 34 may be provided with a head 35 inorder that it may be readily retained in position. The rigid member 29is now placed in position spanning the two adjacent tubes contacted bythe block unit. The shank of eye-bolt 21 passes through an opening 38formed in the base of member 39 and a nut 31 is screwed thereon. Whenthe eyebolt 21 is placed under tension by means of turning up on nut 31it tends to rotate block members I9 and 20 around the respective tubeswhich contact their tube receivingrecesses 23. Inasmuch as the bearingsurfaces 22 on the blocks are eccentric with respect to the'surfaces ofthe tubereceiving recesses 23, there will be a cam action between thetwo blocks which wedges them together and in close contact with thetubes. This force of tension also draws backing member I 29 against thetubes and the result of the wedging action of blocks I9 and 20 and theaction of member 29 is that there is a tendency to spread the tubesapart. This tendency is overcome by securing. adjacent backing members29 together by means of bolts 3 I.

On each corner of the furnace there are provided steel upright members38 protected by refractory blocks 39. Two vertical faces of blocks 39contact the upright members 38 while two other vertical faces contactthe extended ends of corner block members 4i and are thus retainedsecurely in place; One. end of the rigid members 29 adjacent to member38 is secured thereto by means of a bolt 40. As all the rigid members 29are secured to each other by means of bolts 3| there results a rigidbacking structure supported at each end by means of members 38. Thisstructure serves to retain the water tubes I2 in their normal positionand prevents spreading of the tubes due to the wedging action of theblock units I8.

If desired some or all-of the eye-bolts engaging the block units I8 maybe of suflicient length, as shown at 43 (Fig. 2), to extend not onlythrough rigid members 29 but through apertures formed in a horizontalchannel 44 comprising the furnace wall. In this event, a sleeve 45 isprovided around bolt 43, the ends of sleeve 45 bearing against rigidmember 29 and channel 44. Sleeve 45 hence is a compression memberbetween channel 44 and rigid member 29 and forces the latter againsttubes I2. By this arrangement the rigid structure made up of rigidmembers 29 is securely fastened to the remainder of the furnace wall.

As will be seen in Fig. 2, the corner blocks 4| are constructed somewhatdifferently from the blocks I9 and 29. The end of block 4| whichcontacts block 20 is similar to block 28 but the other end of block 4|is extended to contact members 39 as previously explained. With thisarrangement the block member 4I engages the end tube for approximatelyone-half its circumference so that the end tube is securely clampedbetween the block member M and the rigid member to which it is secured.The wedging action of blocks M and 28 is exactly the same as that ofblocks I9 and 29.

A number of block units are placed one above the other on all pairs ofadjacent tubes, thus forming a substantially solid wall. The rigidmembers 29 extend in horizontal rows behind the tubes. It is notnecessary that members 29 in all the rows be secured together by bolts 3I, although this may be done if desired, as I have found that the tubesare prevented from spreading if the members 29 constituting, forinsance, every fifth row are secured together.

After the blocks have been assembled with the backing memberson thewater tubes the spaces remaining therebetween may be filled with aplastic refractory material shown at 42.

.While I have shown one specific embodiment of my invention, it is to beunderstood that modifications thereof which would occur to one skilledin the art fall within its scope which is to be limited only by theappended claims viewed in the light of the prior art.

What I claim is:

1. A furnace comprising two vertical walls meeting to form a rightangle, a pair of upright members adjacent to the apex of said angle, aplurality of vertically extending spaced parallel tubes comprising saidwalls, rigid structures having curved tube recesses, means securing saidrigid structures to each of said upright members, a plurality of blockunits comprising two block members, said block members having curvedtube recesses, tension means engaging said block members and said rigidstructures, and refractory blocks located at the apex of said angle andabutting against said upright members, the block members contacting thetubes adjacent to the apex of said angle being extended to contact saidrefractory blocks and retain them against said upright members.

2. The combination with spaced parallel tubes, of a block unitcomprising two complementary block members between said tubes, saidblock members having curved tube recesses and curved contacting surfaceseccentric with respect to said tube recesses, each block membercontacting a tube for more than one-quarter of the circumference of thetube, rigid backing means straddling the space between said tubes andhaving tube contact recesses and adapted to prevent spreading of thetubes, and stress means engag-i ing said rigid backing means and saidblock members for pulling the block members toward the backing means toexert pressure between the eccentric surfaces, said backing means havingcontact with said tubes for substantially one-quarter of the tubecircumference, and said block membiers and backing means havingoverlapping port ons.

3. The combination with spaced tubes, of a block unit comprising twocomplementary block members between and in front of said tubes, saidblock members having curved tube recesses and curved contacting surfaceseccentric with respect to said tube recesses, rigid backing meansstraddling the space between said tubes and having tube contact recessesand adapted to prevent spreading of the tubes, and stress means engagingsaid rigid backing means and said block members for pulling the blockmembers toward the backing means to exert pressure between the eccentricsurfaces, said block member-shaving rear recesses, and said backingmeans having tube contacting projections extending into the rearrecesses of the blocks.

4. The combination with spaced tubes, of a a block unit comprising twocomplementary block members between and in front of said tubes, saidblock members having curved tube recesses and curved contacting surfaceseccentric with respect to said tube recesses, rigid backing meansstraddling the space between said tubes and having tube contact recessesand adapted to prevent spreading of the tubes, and screw-threaded stressmeans engaging said backing means and said block members for pulling theblock members tor ward the backing means to exert pressure betary blockmembers between adjacent tubes, said block members having tube recessesand contacting surfaces eccentric with respect to the tube recesses, arigid member extending transversely of the tubes and for a distancegreater than the axial distance between adjacent tubes, said rigidmember having recesses to receive said tubes, and stress means engagingsaid block members and said rigid member for pulling the block memberstoward the rigid member to exert pressure between the eccentricsurfaces, the extent of the contact between said rigid member and one ofthe tubes and a block member and said tube being suificient to clamp thetube between said rigid and block members when the blocks are securedthereto.

6. An armored wall structure comprising a-row of spaced tubes, aplurality of armor block units having tube recesses in which the tubesare re ceived, a plurality of rigid members extending transversely ofthe tubes and between adjacent other.

of the tubes, the rigid members engaging the tubes with which they arein contact for substantially one-quarter of the tube circumference, theblock units and rigid members having overlapping portions, whereby thetubes are secured against transverse displacement with respect to eachthey are in contact for more than one-quarter of the circumference ofthe tubes, the other of said two first mentioned means engaging thetubes with which they are in contact for substantially one-quarter ofthe tube circumference, the block units and rigid members havingoverlapping'portions, whereby the tubes are secured against transversedisplacement with respect to each other.

8. An armored wall structure comprising a row of spaced tubes, aplurality of armor block units having tube recesses in which the tubesare received, a plurality of rigid members extending transversely of thetubes and between adjacent tubes and having recesses to receive thetubes, means for securing the block units and the rigid members to thetubes, and means for securing adjacent rigid members together, the blockunits engaging the tubes with which they are in contact for more thanone-quarter of the circumference of the tubes, the rigid membersengaging the tubes with which they are in contact for substantiallyone-quarter of the tube circumference, the block units having recessesin which portions of the rigid members are received, the block units andrigid members having overlapping portions, whereby the tubes are securedagainst transverse displacement with respect to each other.

9. An armored wall structure comprising a row of spaced tubes,- aplurality of armor block units having tube recesses in which the tubesare received, a plurality of rigid members extendin transversely of thetubes and between adjacent tubes and having recesses to receive thetubes, means for securing the block units and the rigid members to thetubes, and means for securing adjacent rigid members together, the blockunits engaging the tubes with which they-are in contact for more thanone quarter of the circumference of the tubes, the rigid membersengaging the tubes with which they are in contact for substantiallyone-quarter of the tube circumference, portions of the block units andrigid members overlapping between adjacent tubes, the block units andrigid members having overlapping portions, whereby the tubcs are securedagainst transverse displacement with respect to each other.

10. An armored wall structure comprising a, row of spaced tubes, aplurality of armor block units, each comprising two complementary blockmembers having tube receiving recesses and contacting surfaces eccentricwith respect to the tube recesses, a plurality of rigid membersextending transversely of the tubes and between adjacent tubes andhaving recesses to receive the tubes, means for securing the block unitsand the rigid members to the tubes, one of said block members and therigid member to which it is secured being arranged to clamp one of saidtubes therebetween, and means for connecting the last mentioned rigidmember to the adjacent rigid member.

11. An armored wall structure comprising a row of spaced tubes, aplurality of armor block units, each comprising two complementary blockmembers having tube receiving recesses and contacting surfaces eccentricwith respect to the tubes recesses, a plurality of rigid membersextending transversely of the tubes and between adjacent tubes andhaving recesses to receive the tubes, means for securing the block unitsand the rigid members to the tubes, .one of said block members and therigid member to which it is secured being arranged to clamp an end tubetherebetween, and means for connecting the rigid member engaging saidend tube to the adjacent rigid member.

12. An armored wall structure comprising a row of spaced tubes, aplurality of armor blocks each having tube receiving recesses, aplurality of rigid members extending transversely of the tubes andbetween adjacent tubes and having recesses to receive the tubes, meansfor securing the blocks and the rigid members to the tubes, one of saidblocks and the rigid member to which it is secured being arranged toengage oppositely disposed portions of the circumference of one of thetubes, said portions being disposed at both sides of the axis of thetube in a direction transverse to the tube axis and substantiallyparallel to the rigid member to clamp said one tube therebetween, andmeans for connecting the last mentioned rigid member to an adjacentrigid member.

13. An armored wall structure comprising a row of spaced tubes, aplurality of armor blocks each having tube receiving recesses, aplurality of rigid members extending transversely of the tubes andbetween adjacent tubes and having recesses to receive the tubes, meansfor securing the blocks and the rigid members to the tubes, one of saidblocks and the rigid member to which it is secured being arranged toengage oppositely disposed portions of the circumference of an end tubesaid portions being disposed at both sides of the axis of the tube in adirection transverse to the tube axis and substantially parallel to therigid member to clamp said end tube therebetween and means forconnecting the rigid member and engaging the end tube to the adjacentrigid member.

14. An armored wall structure comprising a row of spaced tubes, aplurality of armor blocks each having tube receiving recesses, aplurality of rigid members extending transversely of the tubes andbetween adjacent tubes and having recesses to receive the tubes, meansfor securing the blocks and the rigid members to the tubes, one of saidblocks and the rigid member to which it is secured being arranged toengage oppositely disposed portions of the circumference of each endtube, said portions being disposed at both sides of the axis of eachtube in a direction transverse to the tube axis and substantiallyparallel to the rigid member to clamp each of the end tubestherebetween, and means for connecting all of said rigid memberstogether.

15. A furnace comprising walls meeting to form an angle, membersadjacent the apex of the angle, a plurality of spaced parallel tubescomprising said walls, rigid structures having tube recesses, means forsecuring the rigid structures to said members, a plurality of armorblocks having tube recesses, means engaging the blocks and the rigidmembers for securing them to the tubes and refractory blocks located atthe apex of the angle, the blocks in contact with the tubes adjacent theapex of the angle having a portion in contact withthe refractory blocks.

16. A furnace comprising walls including a plurality of spaced tubes,said walls meeting to form an angle, armor blocks having tube recesses,rigid structures having tube recesses, means engaging the blocks and therigid members for securing them to the tubes, and refractory blockslocated at the apex of the angle, the blocks in contact with the tubesadjacent the apex of the angle having a portion in 'contact with therefractory blocks.

MARTIN FRISCH.

